Thermostatically-operated electric switch



Oct. 30, v1928.

R. w. MGBRIEN THERMOSTATICALLY OPERATED ELECTRIC SWITCH Filled may 4, l19m /A/ VEA/TOR.'

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UNITED: STATES ROGER W.l Mosman, or Arron, immers.,

THERMOSTATICALLYOPERATED ELECTRIC SWITCH.

jpplcatonlcd May 4, 1927. Serial No. 188,728.`

My invention has'relation to improve-- ments in thermostaticaily operated electric i switches and consist-s in the novel features `ot construction more fully set 1ortli in the 5 speciiication and pointed out in the claims. The present invention is an improvement overl that shown in my co-pending application, SerialNo. 43,785 filed July 15, 1925,

A in that certain features to appear more fully 1-0.l hereinafter have been embodied to render morey expeditious the `operation of the thermostatic switch. As in the application aforesaid, a body ofmercury is maintained in contacting relation with two conductors oi a '15- circuit by means oil a plug or wan which is caused to be displaced under the application otheat'and lpermit themercuryy to be dislodged, thereby opening that circuit and closing a second circuit. Y,

The principal object the present invention is to provide athermostatically operated switchwheiein suitable means is embodied Afor speeding the response of the switch to changes in temperatureitherein. @ther advantages-are that the-switch is comparatively simple and may be cheaply man uiactured andmay `be used repeatedly. These advantages as well as others possessed by the invention will be better apparent from a detailed description ot the invention in connection with the accompanying drawings, in which Figure 1 represents a panel on which is mounted my improved thermostatic switch together with a signal lamp and alarm, an electrical circuit containing this switch being shown more or less diag-rannnatically; Fig. 2 is a horizontal cross-section talren on the line 2 2 of Fig. l; and Fig. 3 is a side elevation of the panel and the switch which is mounted thereon.

Referring to the drawings, P represents a panel made of a suitable insulating material to which is iiXed in spaced relation three clips 1r, 2 and 3 to the first of which is connected a conductor e, to the second a conductor 5 and to the third a conductor 6. My improved thermostatic switch comprises a tubular casing or receptacle 7 of suitable insulating material, the ends of which are covered with metallic caps S and 9 and the center being provided with a metallic band 10. Shoulders a, b are :termed on the inner surface oi' the casing 7, a short distance inwardly from the ends thereof, and metallic closure members or partitions 11 and 12 are inserted in the ends of casing? andrcaused to set against the shoulders a and I) respectively. 'A short neel; 13 extends inwardly from each closure member and the lopeninglet in the neck and member is traversed by a stem 15 having a valve 16 formed on its inner end and a short cross piece 17 on vits outer end whereby the stem 15 is prevented from pass ing through the opening in the neck 18. The head 16 ot lthe stem 15 ope ates as a valve and the inner end or' neel; 13 as a valve seat therefor for a purpose that will be explained in connectionwith the operation of the device. 4 l f.

,r1 stud 1? projects into the casing I from the center band 10, said stud having electricai connection with the `band 10 and carrying a cross piece 18 on itsinner end together with a cooperatingspring clip 19 for supportving a coil wire 2O within the casing, the .ends oi said 'coil 2O being equally spaced a short distance from the adjacent members 11, 12. There are coils ot wire 21 and-22 disposed within the spaces between member 11 and cap 8, .and member 12 and cap 9 respectively, these coils making electrical connection with the caps and members with which they are in contact. fr body of mercury is placed within the casing` 7 and a plug of waX 24 is arranged to confine said body oi" mercury at one end or' the casing 7 so that it will make cont-act with either member 11 or 12 and one end of the coil 20.

The thermostatic switch is connected into the circuit or any electrically operated apparatus (a lamp' 25 representing such apparatus in the present instance), said circuit bei ing completed by a wire y. A signal lamp 26 and alarm 27 are connected iii parallel with sai-d circuit by being connected between conductors G and wire y.

The operation ot my improved thermostatic switch may now be described as fol- .owsz- In the normal operation et the device, the current will flow from the conductor 5 through the clip 2, coil 20, mercury 23, partition 11, conductor 21, conductor 4, thence throughout the circuit and conductor y. Should there be a short circuit or should there be an excessive load on the circuit, the excess current iiowing through the coil 2O will cause the same to become heated as will also the coil 21, the heating of the coil 20 softening the wax 24 and the heating of the coil 21 increasing the pressure of the gas therein which will be vented through the opening 14 exerting pressure on the mercury 23 and wall 24 so that when the same shall have been softened sufciently, a core (represented by t-he dotted lines Fig. 1) will be dislodged from the wall of Wax allowing the mercury toI escape from its confinement and accumulate on the partition 12. Since the valve 16 closes the opening 14 in the partition 12, the mercury will not enter into the space below the partition, but will close the circuit between the coil 20 and partition 12 thereby causing a current to flow through the circuit comprising lamp 26 and alarm 27 and announcing the fact that something is wrong in the power circuit.

The advantage of the vent in the partitions 12 and 11 is that the pressure created therein and imparted to the wall 24 will provide an escape for the mercury much more quickly than would be the case if no pressure were exerted against the wall. Thus, it will be seen that I have provided a thermostatic switch that is not only certain in its operation but is also quick to respond to the conditions causing it tooperate.

Having described my invention, I claim 1. A thermostatic switch comprising a receptacle of a non-conducting material, a cap on one end of said receptacle, a perforated partition having electrical conductivity within the receptacle and spaced from said cap, a conductor within the casing, means for con* necting one end of said conductor with a. circuit outside the receptacle, a second conductor disposed between the partition and cap and having electri-cal connection with the partition, means for connecting one end of said conductor with said circuit, a fusible insulating wall within the receptacle and spaced from the partition, and a fluent conductor confined between the partition and wall and having electrical connection with the partition.

2. A thermostatic switch comprising a receptacle of a non-conducting material, a cap at one end of said receptacle, a. conductor traver-sing said receptacle and forming one element of an electric circuit, a. fusible insulating wall in contact with said conductor, a fluent conductor held in place by said wall, means within the receptacle for exerting pressure on said wall to dislodge the same and liberate the fluent lconductor when the first mentioned conductor becomes unduly heated.

3. A thermostatic switch comprising a receptacle of a non-conducting material, a metallic cap disposed on each end of said receptacle, one of said caps having connection with. a power circuit and the other with an alarm circuit, a conductor within the receptacle and spaced from said ca s, said conductor having connection with lioth circuits, a fusible wall in the receptacle, a fluent conductor adapted to be sustained by the fusible wall to close the space between the conductor and one cap, and means for effecting a dislodgment of the wall with excessive temv signature.

ROGER W. MCBRIEN. 

